60 Report of the President 



A significant illustration of the wealth of the mineral col- 

 lection is afforded in the satisfactory response the department 

 was able to make to the request of the United States Geo- 

 logical Survey for small pieces of mineral species not available 

 at Washington, to be used in exhaustive determination of 

 the refractive indices of all known individualized mineral 

 compounds. 



No new exhibitions have been made, except such as result 

 from the incorporation of new specimens in the exhibited series. 

 It would seem that a very attractive feature might be added 

 to the Hall of Minerals in the preparation of mineral groups 

 illustrating the mineral-associations of classic American local- 

 ities, and also color-maps to be attached to the pillars, show- 

 ing the mineral resources of the separate states. 



The study collection of the department is practically the 

 entire collection itself as exhibited. There has as yet never 

 arisen the need of a separate assemblage. There has been no 

 expedition or field work and no research or publication, though 

 the design of illustrating and describing Mineral Localities in 

 the United States has not been abandoned. 



EXISTING INVERTEBRATES 

 DEPARTMENT OF INVERTEBRATE ZOOLOGY 



Henry Edward Crampton, Curator 



Owing to many favorable circumstances, the past year has 



been one of unusual activity and profit. Of chief interest and 



_ _. importance is the survey of Porto Rico, con- 



Porto Rico , . , . , . . , XT ' , 



_ ducted under the auspices of the New York 



Survey . 



Academy of Sciences, in which the department 



is cooperating and which is designed to extend over a period 



of five years. In January, Curator Crampton was engaged in 



a reconnaissance of Porto Rico, during which he visited the 



several environmental regions of the island, incidentally 



obtaining interesting material from certain limestone caverns. 



In March, Dr. F. E. Lutz, through the courtesy of Dr. N. L. 



Britton of the New York Botanical Garden, was a member of 



the party which explored the islands of Mona and Desecheo, 



